I guess you could stick a camera out the front of the car, and watch on a screen inside the car. You could have multiple angles, including blindspots.
Anyway, the point is, the screen wouldnt blind you - it would adjust to optimum brightness/contrast.
Perhaps a tad expensive though!

The problem with the corner cube array is that it will reflect the offending light back, well, exactly to the offending headlights, not to the driver wielding the headlights, who may not even notice. Beyond that, the corner cube array generally has a working distance (usually only a few feet) that would hamper its vengeful utility.

How about an automatic headlight orientation and intensity control system? An array of photo-sensors on the car detect the light intensity and orientation from the oncoming headlights, and once a pre-defined annoyance threshold has been met, they dynamically adjust your headlights in orientation and intensity to match theirs.

No offense, but if you are being blinded by the oncomming lights is it really a um bright idea (pun intended) to blind the other driver as well? Personally I like Edmund Land's (found of polaroid) idea of polarizing the windsheilds and the headlights so that glare isn't a problem. But..on to your idea:

I think it would be easier to set up a sensor which detects that the intensity of the light is too high and simply flashed your lights briefly at the offending car. Wouldn't that be simpler than targting a mirror? As for drivers from the rear....auto-dimming mirrors are awesome. They let the other guy see, and prevent him from blinding you